koji build dependencies in cloud computing project?

I just opened bugs #511938, #511941, #511944 to review the 3 new
packages that compromise my little cloud computing project: cld, chunkd
and tabled.

cld and chunkd built just fine in koji, but tabled does not: it
BuildRequires both cld and chunkd.

I thought 'koji chain-build' might help, if I passed all three to
chain-build on the koji cmd line, but there is very little documentation
anywhere on chain-build. Also, chain-build does not support --scratch,
which I wanted to use.

Is there any way to convince koji to SCRATCH build tabled, short of
including cld and chunkd in Fedora rawhide?